On 01/24/2014 09:33 PM, Les Mikesell wrote:
On Fri, Jan 24, 2014 at 1:30 PM, Ljubomir Ljubojevic centos@plnet.rs wrote:
and, even if you have the boot loader on both drives, there's no guarantee your BIOS will boot from the 2nd one. Disks can partially fail in nasty ways that might allow the already-running system to stay up on the other half of the mirror, but when the drive is 'tested' during power up boot sequence, it could hang the system.
True, but forwarding of root mail to admins e-mail address will warn about crash of mirror, so physical intervention of choice can be made. I think manual change in BIOS is of little consequence if system will boot off of surviving disk(s).
Doesn't grub need to know the bios disk id for subsequent stages of the boot and where to find the root filesystem? I think it matters whether or not bios remaps your 2nd drive to the first id.
GRUB boots first partition on a given disk, and then kernel boots file systems from RAID's. Once /boot RAID is mounted, any changes are written to all disks.
And if disks can be hot-swapped then only concern is that GRUB and /boot survive the crash.
And if you know how to do a rescue-mode boot and reinstall grub, you can fix that too.